Field of the Invention
The present invention relates to a colorimetric device, an image forming device, an image forming system, and an image forming management device that make it possible to perform colorimetry of an image that is formed on a transfer medium and that has a color boundary.
Description of the Related Art
As an image forming device such as a printer or a combined machine, there has been what forms an image by printing a color patch on paper, detecting a patch of an output image with a color density sensor or the like, comparing the patch with print base data, correcting print density or the like when there is a difference therebetween in order to increase quality of the output image. A size of a patch printed on paper in such an image adjustment mode is preferably as small as possible in a paper feeding direction in order to reduce paper for adjustment.
Generally, as timing of acquiring a patch image, a method in which a paper detection sensor detects a leading end of paper and a color density sensor detects a patch image at a position of a patch in predetermined timer intervals has been known (see JP 2003-131466 A).
In this method, in an optical sensor for density detection of a patch, a reference position patch is printed on a side of a leading end of paper, a reference position is detected by the density detection sensor itself, and the detected reference position is reflected on subsequent patch density detection timing, whereby a deviation in a density detection position due to attachment accuracy or a chronological change in a sensor of a leading end of paper is prevented. This system is to detect a reference position in paper by a color density sensor itself and to specify a patch position with the point as a reference. Thus, a position of a patch may be deviated when a printing magnification is changed. Thus, when a leading end of paper is a reference, there is a problem that a position of an actually-printed patch may be deviated due to an influence of a leading end position of a print or a magnification error in a paper feeding direction (sub-scanning) and that it is necessary to increase a patch size in consideration of this deviation.
Further, there is what specifies a patch boundary with a sensor to detect a patch image or on a side of image processing.
In JP 2000-039747 A, with respect to a patch read by a CCD or the like, a boundary is identified by application of density to adjacent patches since paper for adjustment is used for a large amount when a gap is formed for a determination of the patch boundary. With this system, it is possible to determine a boundary of a patch and to recognize a patch image correctly. Thus, it is possible to increase the number of patches printed on one sheet of paper.
Recently, color management to acquire a color of a color patch with a colorimeter such as a spectral colorimeter, to create a color profile, and to give a feedback to print data is performed in order to increase quality of a print image. Here, manual scanning of a patch printed on paper is mainly performed with a colorimeter. In-line connection of a colorimeter to an image forming device is more effective for reduction of time for adjustment. With a configuration in which a colorimeter itself detects a boundary of a patch printed on moving paper, it is possible to reduce a patch size as disclosed in JP 2000-039747 A.
A device in which a colorimeter performs manual scanning is generally used. However, a device provided by the present applicant has a specification of moving to a color with a certain color difference in the manual scanning. For example, there is what integrates an amount of reflection light at a plurality of spectral wavelength points after colorimetry, determines that a patch boundary is exceeded when a variation amount exceeds a certain threshold, and performs colorimetry of a next patch or what performs colorimetry of a next patch when a color difference in a color value (L*a*b) or the like acquired from each spectrum exceeds a certain amount. As disclosed in JP 2000-039747 A, a scanning order condition/patch forming condition substantially equivalent to giving a patch density difference is necessary.
However, in the method disclosed in JP 2000-039747 A or a patch boundary determination in a colorimeter in a related art, it is necessary to give a density difference between patches or to give a color difference between patches for a certain degree or more. A patch chart of detecting and correcting a patch includes, for example, a gradation pattern or the like in similar colors. Since there is no constant density difference or color difference in these patches, it is not possible to determine a boundary between patches by a method in a related art. Further, in order to form a patch array with a density difference, it is necessary to make a combination of the certain number of patches. When there is no more patch to which a density difference between patches is to be given, it is necessary to put a dummy gap between patches.
Thus, in a system in a related art, there is a problem that there is a strong restriction in generation of a patch chart.